1. Field of the Invention
The present invention relates to an image output apparatus and an image output method.
2. Description of the Related Art
Recently, in image output apparatuses such as printers, since the data size of the processing target image data has been increasing, there has been a need to improve the processing speed of the image data. To improve the processing speed of the image data, it is necessary to improve the access speed to a recording medium, which is necessary during the image processing stage, as well as the image processing speed itself. This is because image output apparatuses temporarily store the image data during the processing stage of the image data in a recording medium such as a random access memory (RAM) or hard disk.
However, although in the image output apparatus a recording medium which has a large capacity and a fast access speed is required, this is often difficult due to cost restrictions. While volatile recording media, such as RAMs, have a fast access speed, such media are expensive due to their high cost per unit of data capacity. On the other hand, while non-volatile recording media, such as hard disks, can suppress cost increases due to their low cost per unit of data capacity, access speed is slow. Thus, in image output apparatuses, considering the balance between cost and access speed, image processing is performed using a plurality of recording media having different access speeds. Usually, a RAM is used as a work memory, and a hard disk is used as a storage memory. Especially in the case of printing processing, rasterized image data is temporarily held in the hard disk, then read to the RAM in series, and printed.
To improve the data processing speed by using a plurality of recording media having different access speeds, the following method has been proposed. Japanese Patent Application Laid-Open No. 2006-236304 discusses a method for bidirectionally moving data as necessary among different kinds of recording media. In this method, if the data to be accessed is held on a low-speed recording medium, actual access is performed on the data after it has been moved to a faster recording medium. If there is no longer any free space on the recording medium having a faster access speed, the data is moved to a recording medium having a slower access speed in order of older access history.
However, the method discussed in Japanese Patent Application Laid-Open No. 2006-236304 is a method directed to program data in a personal computer (PC). Since no consideration is given to the size of the data to be accessed in the recording medium or the processing order, it is difficult to achieve an increase in speed by applying the technology discussed in this document to an image output apparatus.
In image output apparatuses, image data of different data sizes is processed in page order. Thus, in an image output apparatus that uses a plurality of recording media having different access speeds, to achieve an increase in image data processing speed, it is necessary to control access to the recording media with consideration given to the data sizes of the image data and to the processing order.